AutoAqua’s Smart ATO aquarium system works with a contactless digital sensor that carefully monitors and automates refilling evaporated water by using an advanced infrared optical sensor.  Replacing evaporated water promptly is important in salt water tanks because having less water will change the salinity since salt does not evaporate along with the water, which could be dangerous to fish and corals. This is especially true for smaller tanks. two piece automatic top off sensor and controller with blue frontThe Smart ATO is a sensor and controller all-in-one.  It is integrated with Auto Feedback Security Technology, which provides real-time protection against failure. It also not composed of any moving parts that can fail.

Smart ATO Technical Details

The controller mounts to clear glass or acrylic tank walls using a magnet without difficulty. The maximum wall thickness that can be used with this magnet is a half inch or 12.7 mm. The included DC pump has a flow rate of 74 gallons per hour or 280 liters per hour and a maximum height of 6.5 feet or approximately two meters. The Smart ATO system has a power input of 100 to 240 volts of alternating current and 50 to 60 hertz.

What’s in the Box?

The Smart ATO system comes with a Smart controller, a power adapter, a DC refill pump, two meters of flexible water tube, and a universal bracket holder. The Smart controller senses and controls the auto top off. This controller comes with two parts that connect magnetically; the dry side, which attaches to the outside of the aquarium, and the wet side, which attaches to the inside of the aquarium. The Smart controller also has two DC jacks on its dry side; one to connect to power and another to connect to the pump. The water tube is used with the DC refill pump. The power adapter is a universal power supply for the controller. The universal holder keeps the water tube in place. The Smart ATO also comes with a two year warranty.

Installing the Smart ATO

The Smart ATO is easy to install. Before all else, clean the aquarium wall and ensure it is not dirty. After that, mount the magnetic Smart controller. Be sure to position this at your desired water level. In addition, you should stay away from putting the sensor in an area with bubbles or in direct light. For rimless tanks, attach the universal holder at this time. For rimmed tanks, attach the holder exchange. Then, insert the water tubing into the holder and tighten as needed. The water tube should be positioned higher than the water levels in both the tank or sump and the reservoir to prevent siphoning. Then, insert the water tubing into the DC pump and attach the pump to the bottom of the reservoir. Next, attach the pump wire to the controller. Finally, connect the power adapter to an AC socket and the controller. All the lights on the controller will flash while it initializes. Do not adjust its position during this time. It is recommended that you clean the sensor every 6 months. To change the level of water in your tank or sump, simply move the controller to the new desired level after it has finished initializing.

installation guide for smart ato showing reservoir with dc pump connected to smart controller on tank

Smart ATO LED Indicator

The LED indicator on the controller can tip you off to several problem situations. The green LED is the power light. This light will be on at any time there is power to the Smart ATO system. If this light is flashing at a slow pace, the system is pumping and refilling your tank or sump at present. The blue LED is the alarm light. If it is flashing slowly with an audible alert, there is either a misalignment or algae on the controller. To clear up this problem, first attempt to adjust the alignment of the controller. If that does not work, try cleaning the controller. It will automatically reset when you reattach it. The red LED is the pump light. If this light is flashing slowly with an audible alert, the reservoir water is empty or there is bubble noise. To solve this problem, try refilling the water in the reservoir. If that does not work or the water is not low, try moving the controller away from any bubbles. If it is still flashing, try manually resetting the controller by unplugging it and then plugging it back in. If the red LED is flashing quickly with an audible alert, there is a bad connection or a pump malfunction. To solve this problem, manually reset the controller.


AutoAqua’s Smart ATO is a standout automatic top off system that offers both protection against failure and an easy set up. The small size of the controller and the pump also make the Smart ATO an attractive and nonintrusive choice for any aquarium. It will ensure your water level and salinity are kept stable without having to manually refill your tank daily.


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